1. Field of the Invention
This invention relates in general to fastener devices and in particular to a self-contained fastener device which can releasably fasten itself to one of the two components being fastened and which can releasably fasten the two components together.
2. Description of Related Art
In many diverse fastening operations in which two components are being secured one to the other, it is desirable to have a fastener device which can be releasably secured to one of the two components, and which can releasably secure the two components one to the other. U.S. Pat. No. 2,992,685 (Madsen), U.S. Pat. No. 3,124,190 (Cornell), U.S. Pat. No. 3,578,799 (Davis), and U.S. Pat. No. 3,683,988 (Carter) show some of the existing fasteners of this type and some of the common applications.
Although there exist fasteners of this type that are self-contained--in other words whose component parts are retained together upon unfastening--such existing fasteners are generally bulky and unduly complicated. Smaller, more compact fasteners are desirable for applications in which space is limited. Also, simple fasteners with fewer parts are usually more reliable.
Also, the existing fasteners of this general type must be driven (such as by a wrench) from one particular side of the fastener, which severely limits the range of applications.
The invention of this application is an improvement to the invention disclosed in copending and commonly owned U.S. patent application Ser. No. 08/959,569 (the '569 application), filed on Oct. 28, 1997. Although the invention of the '569 application was a significant improvement over the then-existing prior art, there remain aspects of that invention that can be improved upon. For example, the current invention is structurally different from the invention in the '569 application. The '569 application describes a drive ring that is used to drive a stud into contact with a second object. The current invention uses a retaining cover, which retains the stud in a disengaged position. The stud in the current invention is pushed into contact with a second object by a spring.
The structural differences between the current invention and the invention described in the '569 application allow for functional improvements in the current invention. The current invention, because it uses a retaining cover instead of a drive ring, has increased floating capability of the stud. This increased floating capability allows the stud to more easily engage the threads of the second object when the second object is being connected to the first object.
The elimination of the drive ring in the current invention also reduces maintenance. In the current invention, there is little or no maintenance associated with normal use of the fastener. With both the current invention and the previous invention it is important that the stud be able to "free spin" after it is placed in the disengaged position. The stud is screwed into the housing to place it in a disengaged position. If not for the free spinning feature of both inventions, continued rotation of the stud once in the disengaged position would cause the housing to become disengaged from the first object. In the previous invention, the free spinning feature caused excessive wear of the drive ring, which required maintenance to replace the drive ring. In the current invention, the drive ring has been eliminated, thereby eliminating the need for frequent maintenance.
A more in-depth description of the improvements of the current invention over the invention in the '569 application is detailed in the Detailed Description of the Preferred Embodiment of this application.